There is known an electric toothbrush of a type which performs toothbrushing (removing food debris and plaque) by placing a fast-moving brush against teeth. For the electric toothbrush of this type, a variety of driving mechanisms and driving methods are proposed with the aim of improving plaque removing power and improving sense of medical treatment.
For example, Patent Documents 1, 2 disclose an electric toothbrush capable of switching between a rotational reciprocating motion (rolling motion) and a linear reciprocating motion by switching rotational directions of a motor.
Furthermore, Patent Document 3 discloses an idea that the orientation around the shaft of the toothbrush body is detected at four stages or eight stages and a section being brushed is estimated based on the detection result. Specifically, a plurality of segments each in the shape of a sector are provided in the circumferential direction in the inside of the body. The orientation of the toothbrush body is estimated by sensing in which segment a conductive ball is present, based on a change of electric resistance. However, it is difficult to reduce the size of such a mechanism, and in addition, it is difficult to obtain high sensing accuracy because the position of the ball is not stable due to motion of the toothbrush. In Patent Document 3, the number of times or time of brushing is recorded for each section, and evaluation as to whether brushing is properly done or not is output.
Patent Document 1: Japanese Utility Model Laying-Open No. 4-15426
Patent Document 2: Japanese Patent Laying-Open No. 5-123221
Patent Document 3: Japanese Patent Laying-Open No. 2005-152217